Machinery for vacuum tube manufacture



Aug. 24, 1948. w, MOSCRIP A4752 MACHINERY FOR VACUUM TUBE MANUFACTURE Filed May 9, 1944 By W/Q A itorney Patented Aug. 24, 1948 UNITED STATES *sP MAGHI'NERY' FOR .VAGUUM TUBE MANUFACTURE William "Roswell Moscrip,*London, England, as-

signor, "by mesne assignments, to International Standard Electric Corporation, New York, N. Y., a'corporation of Delaware Application May 9, 1944, Serial No. 534,790 In Great Britain 'May"21, 1943 12 Claims. (Cl. 49--2) The'present invention relates to improvements 'ofthe 'rod remainsfixed in space' and inclined to -in machinery "for the manufacture of vacuum theaXis-ef rotation. "tubes andthe like, and is principally concerned According "to another aspect the invention'prowith'means for formingcircular stems for such Vides an arrangement for sealingtogether the tubes an'dsealing conductor wires through the 5 endsoi-two' tubes of fusible 'material-co aiiially "stems. arranged one inside the other, comprising a hol- One commonly used form of stem for a vacuum low cylindrical die having a flat end arranged tube "consists of a relatively wide glass tube iii-proximity to the ends of the tubesto be sealed, 'flared -at oneend for sealing to theenvelope and 'meansior ro'ta'tingthe die and tubes-about the 'joined at the other end byan annular seal to a same axis-heating means for softening the ends eo axialexhausttube of smaller diameter passing of the tubes, and means operable externally to throngh-thefiared'tube. The conductors for the the die during rotation -for transferring an-inelectrodes inside'th'e envelope are sealed through "t'ernal forming roller from its normal position 'the annular seal and'pa'ss out in the space beinside thedieinto theend ofthe inner tube, and

twe'en'the' two tubes. pressing it into=c'ontact with the softened wall It is common practice to manufacture stems thereof.

for vacuumtubesonamulti-head-machine com- The invention will be described with reference prising an indexing table on which are mounted to the accompanying drawings in which:

a plurality of stem heads in each-of which'a stem Fig. 1 shows aside View with certain parts in 'to be formed may be rotated opposite sets of section of a stem'head equipped with a fo'rmin'g burners for softening the glass. The table is arrangement according to the invention; and

periodically rotated in steps about a vertical axis Fig. 2'shows a 'partialsection-view 'a-t 2-2 of so as to bring the stem heads successively to posi- "Fig. l'to an enlarged scale toshowa detail.

tion of progressively increasing heating, and/or "Referr ing' to Fig. L the-stem head lathe comto'position where a forming operation is perg5-p1-iS hapedframe'whichmay' fi dto-an :formed. 'index-ingtable of any suitable'type. The frame The object of the present invention is to simhas anupright member 4, and upper and'lower "plify and improve the manufacture of circular horizontal members 5 and 6.

stems of the kin'd described by providing the stem The main rotating shaft of the latheis'a tube head with an automatic tool which joins the two "I, to the upper end of which is pinned-a hori- -p'a-rts of the stem and seals the conductors therezontal 'gear whe'el 8 bymeans of the pin9. "Ihe through in one operation. tube runs'on main ballbearingslll and H, an'd'is "While such a tool will be of particular advancaused 'to rotate by a gear-wheel l8 driven by :a tage when used in a multi-head indexing mamain driving wheel '(not shown) mounted on chine, it is not confined to this type of machine, the indexing table. The gea -wheel 18 may be but could be employed in a single head machine solidly'fixed' to the tube 'lyor as shownin Fig. 1,. it

making only one stem at a time, if desired, may be coupleditheret'o through a frictionclutch It is to be noted that'in the manufacture of comprising a 'cone I l keyed to the'tube l, and circular stems, it is desirablethat the heating of pressed into a conical recess in the gear wheel 'theglass should be perfectly even and that the 18 by a spring I1. The pressure is regulatedfby heating names should not be periodically inter- 'adisc It on which the spring bears, and which rupted' by the frame or other moving part of the can be screwed up theitube 'Lits'pOsition being stem head. For this reason, the stem head should maintained y p urged upwards by a preferablyb'e'of thevertical-lathe type, and-the spring (not shown) and carried by a collar [3 tool to be described below is therefore adapted to 4 5 fixed 'tothe tube 1. The pin l5 enters one of a this'kin'd of stem head or lathe. "number of "equally spaced holes in the disc 16. According to the invention, there is provided A collar I2,'also'fixedt-o the tube '1, forms a thrust an arrangement for forming a circular press from bearing for the gear-wheel Hi. If 'it should be parts of fusible material, comprising a hollow 'desired'to stop rotation of the work, a stop'm'emcylindrical member containing a longitudinal rod "her (not shown) can be'made to en'gage'the procarrying at one end a forming roller, means for jecting portion of the collar l2, thus stopping the rotating the parts and the member about the "mainsh'aft while'the'clutch slips'andallows'the same axis, and means operable from outside the gear-wheel 18 to continue its rotation. hollow member for tilting the *rod about a ful- A smaller tube-l9 fitsxsmoothly inside'the tube crum so that whllethe member-rotates, the'axis "1 andis'keyed'thereto by means shown at A,Fi'g.

, or tool according to the invention.

The gear-wheel 8 drives another gear-wheel 2i fixed to a vertical counter-shaft 22 carrying at the upper end a second gear-wheel 23 similar to 2!. Th wheel 23 drive a gear-wheel l4 similar to 8 which runs on a horizontal circular hearing 25 of large diameter, and carries a, stem holder 26 fixed thereto in an easily removable manher, and adapted to grasp a stem blank 21 and a co-axial exhaust tube by clamps 28 and 29, respectively. The bearing 25 has a circular central clearance hole providing space in which the stem holder may rotate. A fixed burner for heating the stem blank may be placed as shown at 30. A group of similar burners may be used, if desired.

It will be understood that the gear-wheel 24 carrying the holder 26 will rotate synchronously with the gear-wheel 8, so that the stem blank 21 and the tube 5| will rotate at the same speed and will have no relative movement provided the stem blank and tube are properly centred by means of the clamps.

Above the lower horizontal member 6 of the frame is mounted a press-forming arrangement This tool comprises a hollow die 52 fixed co-axially to the upper end of the tube l9 by means of the collar 53. 'I'he die has a reduced portion which slips inside the tube l9, and carries at its upper end a. number of locating holes 54 into which may be inserted the conductors 55 which have to be sealed through the press.

Inside the die 52 is placed a longitudinal rod 56 carrying a ball 5'! which slides snugly inside The upper end of the rod 56 carries a roller 58 which in the unoperated position of the tool shown is just below the upper surface of the die.

.The lower end of the rod 56 is fixed to the centre ,of a wheel 59 held in a crutch 60, the forms of which are seen in the section view of Fig. 2.

This wheel has three spokes 6|, and the tube 19 is provided with three equal slots 62 cut longitudinally from the upper end down as far as a point just below the wheel 59. These slots are wide enough to provide relatively large clearance for the spokes of the wheel 59 as indicatedin Fig. 2. The crutch 69 provides an appropriate bearing in which the wheel 59 may rotate,

It will be understood that the wheel 59 with the rod 56 attached can be slipped down the tube I 9 with the spokes 6! in the slots 62 until the wheel enters the crutch 66, and the hollow die 52 can then be slipped over the rod 56 and ball 51 until it rests on the upper edge of the tube l9, being then held in place by the collar 53. In Fig. 1, the rod 56 can be seen through one of the slots 62.

The main lever 63 is hinged at 64 to the upright member 4 of the frame and carries a bush 65 in which a rod 66 attached to the crutch 66 can slide horizontally. The main lever also carries a vertical lever 61 hinged at 68 and carrying at the upper end a roller 69 which is just opposite the top of the die 52.

The rod 66 carries a cam block which rests upon a ball H mounted at the top of a plunger 41. The turned down tail 12 of the vertical lever 61 also rests on the ball H on a chamfered edge ball 57.

4 15 as shown, and the block 10 and tall 72 are urged together by a spring I3.

Before making the press, the stem 21 and exhaust tube 5| are arranged co-axially close to the top of the die 52, with the conductor wires 55 standing in the holes 54 between the two tubes. The glass is then heated with the die 52' and holder 26 rotating together until tufiicienily softened, when the plunger 41 is pushed upwards by suitable means (not shown). The first effect is to raise the main lever 63 together with the crutch 60 and the vertical lever 61. This brings the two rollers just above the top of the die, the wheel 59 rising in the slots 62 and carrying the rod 56 with it, An adjustable stop 14 in the heel of the main lever 63 now comes up against the vertical frame member 4 and prevents the lever 63 from moving further. The plunger 41, however, continues to be pushed upwards and now spreads apart the block 10 and the tail 12 of the lever 61. The crutch 60 is thus moved sideways and carries with it the wheel 59, which, as will be seen from Fig. 2 is able to move a short distance in the direction of the arrow It on account of the clearance between the slots 62 and the spokes 6|, whatever be the position of the spokes with respect to the crutch. The wheel 59 swings the lever 56 anti-clockwise (Fig. l) pressing the roller 58 against the lower inside end of the exhaust tube 5|. The lever 61 is at the same time rotated clockwise pressing the roller 69 against the lower outside end of the stem 21. The combined effect of the two rollers is to squeeze the molten glass round the conductor wires, sealing the stem 21 to the tube 5!, and making a joint looking substantially as shown in Fig. 1. On release of the plunger 41, the parts of the forming tool return to the initial positions shown.

The wheel 59 provides a means by which the rod 56 may be operated from outside the rotating tube 19 in such a manner that the axis of the rod 56 remains substantially fixed in space, making a small angle with the axis of rotation. By shifting the wheel 59 sideways it is constrained to rotate about a point which is not on the axis, and it causes the axis of the rod 56 to be held fixed in space at a small angle with the axis of the die 52 by the crutch 66 and the At the same time the rod 56 rotates about its inclined axis because of the rotation of the wheel 59.

It should be added that the wheel 59 is preferably rigidly fixed to the rod 56, in which case it would tilt slightly when the crutch 66 moves to the right. As the movement is small, it would not be diificult to accommodate the tilt. Furthermore, this wheel does not necessarily have three spokes. It could have any number, for example, only one, in which case the greatest freedom of movement would be obtained, but it would perhaps not be very stron mechanically. Clearly, the tube 19 should have the same number of slots as there are spokes in the wheel 59.

It will be understood that although the stem and tube will be most usually made of glass, the same kind of tool could be used with other fusible materials such as quartz, for example. The tool could be adapted for use with any other kind of stem head working on the lathe principle in which the means for rotating the parts are mounted in a fixed frame and provide uninterrupted access to the heating flames.

What is claimed is:

1 In a machine'for the manufacture of vacgamma imm tubes;v a circular: stem. forming v device comprising a. cylindrical member; for supporting the stem, a rod pivotally mounted intermediate; its ends. in the member and having a forming roller at one end thereof to contact the internal surface of-t-he' stem, a wheel secured to said rod and extending outside said cylindrical. member, a second forming roller mounted to contact the outersurface of the stem, a pivotal mount for saidsecond forming roller, and meanspressing against said wheel and said pivotal mount for forcing said rollers against the outer and internal surfaces of said stem.

2.- A: device for forming a circular press from parts of fusible material comprising a frame, a support for the parts of fusible material rotatably mounted in -sa-id frame, a hollow cylindrical member rotatably mounted in said frame with one end adjacent to said support, a longitudinal rod contained in said member and having a fulcrum therein intermediate its ends, aforming roller'l'ocated at the end of said rod adjacent to the said one end of said member, rotating means connected to saidhollow cylindrical member and to said support for rotating saidparts and said cylindrical member about a common axis, a wheel secured to said rod and extending outside said cylindrical member, and means mounted on the frame pressing against said wheel and operable from outside said hollow member for tilting said rod about the fulcrum whereby, While said memher and support rotate, the axis of said rod remains fixed in the cylindrical member inclined to the axis of rotation thereof.

3. A device for sealing together the ends of two' tubes of fusible material co-axially arranged one inside the other comprising a frame, a support for the tubes rotatably mounted in said frame, a. hollow cylindrical die rotatably mounted in said frame, and terminating adjacent to said support for pressing against the ends of the tubes to be sealed, a rod in said die having a forming roller at the end' thereof adjacent to said support, means connected to said die and said support for rotating said die and said tubes about a common axis, heating means arranged adjacent to thetermination of said die for softening the ends of said tubes, a wheel secured to said rod and extending outside said cylindrical die and means. mounted, on said frame pressing against said wheel and operable externally to said die during rotation for transferring said internal forming roller from an inoperative position inside sai'd die into the end of the inner tube and pressing it into contact with: the softened wall thereof.

' 4'. A device :for sealing a tubular glass stem to an inner coaxial glass exhaust tube comprising a frame, a support for the stem and tube rotatably mounted in said frame, a hollow co-axial cylindrical die rotatably mounted in said frame and terminating adjacent to said support for pressing against the ends of the stem and tube to be sealed, a rod in said die having a forming roller at the end thereof adjacent to said support, means connected to said support and said die for rotating'said' die and said glass stem and tube about a common axis, heating means arranged adjacent to the termination of said die for softening the glass of both said stem and tube, a wheel secured to said rod and extending outside said cylindrical die, means mounted on said frame pressing against said wheel and operable externally to said die during rotation for slidin said roller out of said die into the end of 65- said exhaust tube; an external forming; roller movably mounted on said frame adjacent to. the termination of said die, and means on the frame connected to said external roller for moving said external roller to aposition outside said stem and opposite said internal roller and. for. moving said external" roller. towards the softened. ends of saidrotating glass stem and. tube.

5. A device for sealing a tubular lassstem to an inner coaxial. glass. exhaust tube comprising a frame, a support. for the. stem and tube. rotatably mounted in said frame, a hollow co-axial cylindrical die rotatably mounted insaid frame and: terminating adjacent to said support .for pressing against the. ends of the stem and tube to be sealed; a rod in said die having an internal forming roller at the end thereof adjacent to said support, said rod' having a fulcrum comprising aball fixed to said rodand fitting closely inside said die, means connected toxsaid diev and support for rotating said die and stem and tube about a common axis, heating means arranged adjacent to the termination of said die for softening the ends of said stem and. tube, a wheel secured to said rod and extending outside said die and. means mounted on said frame pressing against. said wheel and: operable externally to said die during rotation for transferring said internal forming roller from an inoperative position inside said die intotheend of said inner tube and pressing it into contact with the softened wall thereof and for tilting said rod about its fulcrum to force the internal forming roller against the heated ends of the tubes.

6. A device for sealing together the ends-of two tubes of fusible material coaxially. arranged one inside the other comprising a frame, a support for the tubes rotatably mounted in said frame, a hollow cylindrical die rotatably mounted in said frame with one end adjacent to said support for pressing against the ends of the tubes to be sealed, a rod in said die having an internal formin roller at the end thereof adjacent to said support, said rod having a fulcrum comprising a ball fixed to said rod intermediate its ends and fitting closely inside said die, means connected to said die and said support for rotating said die and tubes about a common axis, heating means arranged adjacent to the terminationv of said die for softening the ends of the tubes, an external forming roller having means pivotally mounting it on said frame adjacent to the termination of said die, a wheel secured to said rod and extending outside said cylindrical member, and means mounted on said frame pressing. against said wheel and said pivotal mounting means. and operable externally to said die during rotation for tilting said rod around said. fulcrum. for thus transferring said internal forming roller from an inoperative position inside said die into the end of the inner tube and pressing it into contact with the softened wall thereof and for pressing said external forming roller against the outer tube, said wheel being arranged with its axis parallel to the axis of rotation and having at least one spoke, the center of said wheel being connected to the end of said rod remote from that to which said internal forming roller is attached, said means for rotating said die comprising a tubular drivingv shaft to which said die is coaxially fixed and having at least one slot therein through which said spoke projects.

7. A sealing device according to claim 6, in which said slot is formed so as to provide sufiicient. clearance for the spoke of said wheel to allow the axis of said wheel to be displaced by a predetermined distance from the axis of rotation thereof.

8. A sealing device according to claim 6, in which said slot is formed so as to provide sulficient clearance for the spoke of said wheel to allow the axis of said wheel to be displaced by a predetermined distance from the axis of rotation thereof, said means for tilting said rod including a crutch in which said wheel is mounted so as to provide an appropriate bearing therefor and surrounding said tubular driving shaft, said crutch being arranged so as to slide in a direction perpendicular to the axis of rotation of said wheel.

9. A sealing device according to claim 6, in which said slot is formed so as to provide sufficient clearance for the spoke of said wheel to allow the axis of said wheel to be displaced by a predetermined distance from the axis of rotation thereof; said means for tilting said rod including a crutch in which said wheel is mounted so as to provide an appropriate bearing therefor and surrounding said tubular driving shaft and being arranged so as to slide in a direction perpendicular to the axis of rotation of said wheel, and a main lever pivoted at a fixed point on the frame and a bush carried thereby in which said crutch may slide, said lever being so positioned that when pivoted about said fixed point through a small angle from a rest position, said wheel is moved parallel to the axis of rotation, thereby moving said internal roller into the end of said inner tube.

10. A sealing device according to claim 6, in which said slot is formed so as to provide suflicient clearance for the spoke of said wheel to allow the axis of said wheel to be displaced by a predetermined distance from the axis of rotation thereof; said means for tilting said rod and for pressing said external roller including a crutch in which said wheel is mounted so as to provide an appropriate bearing therefor and surrounding said tubular driving shaft and being arranged so as to slide in a direction perpendicular to the axis of rotation of said wheel, a main lever pivoted at a fixed point on the frame and a bush carried by said main lever in which said crutch may slide, said lever bein so positioned that when pivoted about said fixed point through a small angle from a. rest position, said wheel is moved parallel to the axis of rotation, thereby moving said internal roller into the end of said inner tube, and a second lever carrying said external forming roller and pivoted to the end of the main lever, so that when the second lever is pivoted said external roller is ioved toward said internal roller.

11. A sealing device according to claim 6, in which said slot is formed so as to provide sufficient clearance for the spoke of said wheel to allow the axis of said wheel to be displaced by a predetermined distance from the axis of rotation thereof; said means for tilting said rod and pressing said external roller including a crutch in which said wheel is mounted so as to provide an appropriate bearing therefor and surrounding said tubular driving shaft and being arranged so as to slide in a direction perpendicular to the axis of the rotation of said wheel, a main lever pivoted at a fixed point on the frame and a bush carried thereby in which said crutch may slide, said lever being so positioned that when pivoted about said fixed point through a small angle from a rest position, said wheel is moved parallel to the axis of rotation, thereby moving said internal roller into the end of said inner tube, a second lever carrying said external forming roller and pivoted to the end of the mainlever, so that when the second lever is pivoted said external roller is moved toward said internal roller, 9. plunger formed and positioned so as to operate said levers, a ball on one end of said plunger, and a pair of cam blocks one attached to said crutch and the other to said second lever and in contact with said ball.

12. A sealing device according to claim 6, in which said slot is formed so as to provide sufiicient clearance for the spoke of said wheel to allow the axis of said wheel to be displaced by a predetermined distance from the axis of rotation thereof, said means for tilting said rod and pressing said external roller including a crutch in which said wheel is mounted so as to provide an appropriate bearin therefor and surrounding said tubular driving shaft and being arranged so as to slide in a direction perpendicular to the axis of rotation of said wheel, a main lever pivoted at a fixed point on the frame and a bush carried thereby in which said crutch may slide, said lever being so positioned that when pivoted about. said fixed point through a small angle from a rest position, said wheel is moved parallel to the axis of rotation, thereby moving said internal roller into the end of said inner tube, a second lever carrying said external forming roller and pivoted to the end of the main lever, so that when the second lever is pivoted said external roller is moved toward said internal roller, a plunger formed and positioned so as to operate said levers, a ball on one end of said plunger, a pair of cam blocks one attached to said crutch and the other to said second lever and in contact with said ball of the plunger, and an adjustable stop for said main lever bearing against said frame after said main lever has been pivoted through a predetermined angle by said plunger, whereby further operation of said plunger causes said cam blocks to be urged apart by said ball on the plunger, thereby causing tilting of said rod inside said die and also pivoting of said second lever about its pivot so that said two forming rollers approach one another.

WILLIAM ROSWELL MOSCRIP.

REFERENCES CITED The following references are of record in the file of this patent:

' UNITED STATES PATENTS Number Name Date 418,235 Schulze-Berge Dec, 31, 1889 1,006,383 Johns Oct. 17, 1911 1,730,926 Fitch Oct. 8, 1929 1,914,205 Hooper et a1. June 13, 1933 2,266,417 Eisler Dec. 16, 1941 FOREIGN PATENTS Number Country Date 13,609 Germany June 9, 1881 

